Experiments in which quantum rods conjugated to the protein transferrin crossed a laboratory model of the blood-brain barrier point to a nanotech method for ferrying various diagnostic and therapeutic molecules across the blood brain barrier. The researchers expect protein-conjugated quantum rods to be able to transport multiple agents across the blood-brain barrier so that they could function synergistically. From a Nanowerk Spotlight, written by Michael Berger “Crossing the blood-brain barrier with nanotechnology“:
The challenge in treating most brain disorders is overcoming the difficulty of delivering therapeutic agents to specific regions of the brain by crossing the blood-brain barrier (BBB). This barrier — a tight seal of endothelial cells that lines the blood vessels in the brain — is a physiological checkpoint that selectively allows the entry of certain molecules from blood circulation into the brain. … while the BBB naturally evolved in order to protect the brain from invasion of various circulating toxins and other harmful molecules, it also serves as a major impediment towards the brain-specific delivery of various diagnostic/therapeutic molecules needed for combating various neuronal disorders.
To date, delivery of therapeutic molecules into the brain often involves highly invasive techniques (like drilling a hole in the skull). The utter scarcity of techniques for brain-specific delivery of therapeutic molecules using non-invasive approaches has led researchers to increasingly explore the vast potential of nanotechnology toward the diagnosis and treatment of diseases/disorders incurable with present techniques.
Scientists have now reported a nanoparticle-based platform which ‘tricks’ the BBB into allowing the entry of the nanoparticle into the brain, using an approach that draws parallel to the ‘trojan horse’ concept. Certain proteins and peptides, such as the iron-transporting protein transferrin, are allowed free access across the intact BBB as they function as carriers of essential nutrients into the brain. By linking transferrin with rod-shaped semiconductor nanocrystals (quantum rods) — an up and coming diagnostic agent which can also multitask as carriers of therapeutic molecules — it was found that the transferrin helps the linked quantum rods to ‘sneak’ across the BBB into the brain. This finding can have significant potential implications towards the development of brain-directed nanoparticle based diagnostic and therapeutic agents using minimally invasive procedures.
The research was published in the journal Bioconjugate Chemistry (abstract).